Did you try a clay bar? Strong acid cleaners are really the final step. Even Meg's Wheel Brightner says don't use on aluminum. I bet this is a similar product. The wheels on my friend's Evo were great but had a light yellowing to them at the ends. When it came back from the autobody shop it was gone. The guy used super-aggressive wheel acid and the stuff came right off. Risky, but effective.